NES 2.0 Mapper 540
NES 2.0 Mapper 540 is a variant of NES 2.0 Mapper 359 that rewires the PPU/CHR address lines to select 2 KiB instead of 1 KiB banks in order to address 512 KiB of CHR-RAM with 8 bit CHR banking registers. It is used on a “Super Boy” mapper hack of Master Fighter VI’, originally for NES 2.0 Mapper 264. Its UNIF board name is UNL-82112C.
Pin Connected to
PPU A10 CHR-ROM A10
PPU A11 ASIC PA10
PPU A12 ASIC PA11+PA12
ASIC CHR A10 CHR-ROM A11
: :
ASIC CHR A17 CHR-ROM A18
So that the ASIC sees the followings addresses:
Real PPU Addr ASIC PPU Addr
$0000 $0000 -> reg $A000
$0400 $0000 -> reg $A000
$0800 $0400 -> reg $A001
$0C00 $0400 -> reg $A001
$1000 $1800 -> reg $B002
$1400 $1800 -> reg $B002
$1800 $1C00 -> reg $B003
$1C00 $1C00 -> reg $B003
Mask: $F003
- $A000: Select 2 KiB CHR-ROM bank at PPU $0000-$07FF
- $A001: Select 2 KiB CHR-ROM bank at PPU $0800-$0FFF
- $A002: No function
- $A003: No function
- $B000: No function
- $B001: No function
- $B002: Select 2 KiB CHR-ROM bank at PPU $1000-$17FF
- $B003: Select 2 KiB CHR-ROM bank at PPU $1800-$1FFF